<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <html> <head> <META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=us-ascii"> <meta name=Generator content="Microsoft Word 10 (filtered)"> <style>  </style> </head> <body lang=EN-US link=blue vlink=blue> <div class=Section1> The problem is that each panel’s compression characteristics will be different or, you could say, have its own distinct personality.  Not only in terms of how much compression they will take at the outset which will determine how much crown will form initially, but how well it will withstand the compression in the short and long term.  Some panels change quite a bit from the factory to the showroom floor and almost all of them change within the first year or two.  In an environment with large humidity swings they will change even more.  I don’t know how you would be able to predict that with any degree of accuracy.  If one insisted on having compression in the panel then the best way is probably a hybrid system where you underbuild the precrowned rib support somewhat counting on a certain amount, but less, compression to achieve the rest of the requisite stiffness.  You still have the unpredictability of the panel’s unique ability to withstand compression, but reducing the amount might create a somewhat more stable system. <div> David Love davidlovepianos@comcast.net www.davidlovepianos.com </div> -----Original Message----- From: pianotech-bounces@ptg.org [mailto:pianotech-bounces@ptg.org] On Behalf Of Jude Reveley/Absolute Piano Sent: Monday, February 11, 2008 6:05 AM To: Pianotech List Subject: Re: Soundboard stiffness variances   <div>   </div> <div>   </div> <div> > The problem, as has been outlined many times, is not that the RC&S people > aren't interested in the predictability of the CC system, it's that the CC > system is by its nature unpredictable both in terms of the initial outcome > and the long (or short) term prognosis and sustainability.     > > David Love > <a href="mailto:davidlovepianos@comcast.net">davidlovepianos@comcast.net</a> > <a href="http://www.davidlovepianos.com">www.davidlovepianos.com</a> </div> <div>   </div> <div> Well put, David. My instinct and experience would lead me to agree. It would sort of be like measuring Heisenberg's particle in that the very stiffness we would try to measure is always changing, just by our very breath as we lean over the thing to examine it.  </div> <div>   </div> <div> Jude Reveley, RPT Absolute Piano Restoration, LLC Lowell, Massachusetts (978) 323-4545 </div> </div> </body> </html>